CN211112522U

CN211112522U - Double-thread splicing needle and thread presser foot device for crank arm type sewing machine

Info

Publication number: CN211112522U
Application number: CN201921802773.6U
Authority: CN
Inventors: 赵玉荣
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2020-07-28
Anticipated expiration: 2029-10-24

Abstract

The utility model provides a crank arm formula sewing machine is with double-line concatenation needle line presser foot device, including single presser foot and screen flower hook drive fan-shaped piece, single presser foot and screen flower hook drive fan-shaped piece run through the presser foot push rod of sewing machine aircraft nose, the presser foot push rod perforation both sides of single presser foot are provided with right screen flower long looper fixed sleeve and right screen flower short looper fixed sleeve respectively, the presser foot push rod perforation upper end edge of screen flower hook drive fan-shaped piece then is provided with left screen flower frame fixed cylinder, the pivot of right screen flower long looper actuating lever is vertical runs through right screen flower long looper fixed sleeve, and the lower extreme is fixed with the right screen flower long looper of hook body on the right side, right screen flower long looper actuating lever horizontal part then rotates through the left side of right screen flower long looper drive connecting rod with screen flower hook drive fan-shaped piece to be connected, the pivot of right screen flower short looper actuating lever is vertical runs through right screen flower short looper. The utility model discloses can sew two parallel stitches simultaneously, more can embody the individuality of product and the aesthetic feeling of seam lines.

Description

Double-thread splicing needle and thread presser foot device for crank arm type sewing machine

Technical Field

The utility model relates to a sewing machine part, a crank arm formula sewing machine is with double-line concatenation needle and line presser foot device specifically says so.

Background

In recent years, with the continuous development of domestic clothing industry, the sewing equipment industry is continuously upgraded, and various sewing equipment is continuously emerged. Various auxiliary parts are indispensable in the sewing equipment, wherein the presser foot auxiliary part is an indispensable component in a feeding mechanism of the sewing equipment, and the presser foot auxiliary part has the functions of pressing or clamping sewing materials to ensure reliable feeding of the machine and ensure smooth formation of a thread ring of a needle thread and reliable hooking of the thread hooking device. For example, the currently commonly used star keen brand crank arm type four-needle six-thread sewing machine (model FW-740TB) has the main advantages that:

1. adopt centerless motor, shake for a short time, the noise is low, and the sewing is more level and smooth, and the dismouting is more convenient, and the performance is more stable. The main shaft and the motor are driven coaxially, a motor core is not arranged, and the balance coefficient is higher.

2. The ceramic thread passing structure with special treatment is adopted, so that the friction coefficient is reduced, the sewing is smoother, and the service life of the machine is effectively prolonged.

3. An infinite circulation mode is adopted to lubricate an oil way, the front cover is sealed, a reverse flow design is adopted, oil leakage is avoided, and the problem that a machine is stuck is effectively solved.

4. The new design of hidden presser foot lifting mechanism is combined with the machine base innovatively to add beauty and shock-absorbing. The elastic sheet type presser foot mechanism is adopted to customize different presser foot skins aiming at different fabrics, so that the thin materials and the high-elasticity fabrics for the underwear can be fully corresponded.

5. The front and back needle protection devices adopting the patent design (CN201510099251.4 and the like) ensure perfect stitches of the machine in high-speed operation and are not easy to break. The utility model discloses a two piece cloth seam departments of general underwear are used for the concatenation seam and the reinforcement, the bone piece is crossed to men's pants bottom of a trouser leg, and women's tights pastes the strip reinforcement, the piece, and the complete driving fit piece of double-colored cloth etc. and product seam department is more level and more smooth, reduces with human friction, has increased the travelling comfort of product, consequently by industry wide use.

In the fields of knitting, clothing, bedding and the like, a plurality of high-end products pursue humanization and fashion of products, particularly clothing, but the crank-type four-needle six-thread splicing and sewing machine can only sew through a right-side thread hook, and the sewn upper-thread pattern stitch can only be in one color. Therefore, the color matching is monotonous, and the single color trace has limitations on product research and development and humanization of the product. The utility model discloses an improve on prior art's basis, change original presser foot device structure through innovatively, make it can sew out two parallel stitches simultaneously, two parallel stitches can arrange according to the product at will on the color, make the product hit look and the line feel strengthens greatly, have improved the aesthetic property of product, also make the diversified market of product adaptation equally.

SUMMERY OF THE UTILITY MODEL

In order to solve the above problems, the present invention provides a double-thread stitching needle and thread presser device for crank arm type sewing machine.

In order to achieve the above purpose, the technical scheme of the utility model is that: a double-thread stitching needle thread presser foot device for a crank arm type sewing machine comprises a single-cut presser foot and a screen flower hook driving fan-shaped sheet, wherein the single-cut presser foot and the screen flower hook driving fan-shaped sheet are penetrated through by a presser foot push rod of a sewing machine head, a right screen flower long looper fixing sleeve and a right screen flower short looper fixing sleeve are respectively arranged on two sides of a presser foot push rod perforation of the single-cut presser foot, a left screen flower stand fixing cylinder is arranged on the upper end edge of a presser foot push rod perforation of the screen flower hook driving fan-shaped sheet, a rotating shaft of a right screen flower long looper driving rod vertically penetrates through the right screen flower long looper fixing sleeve, a hook body is fixed at the lower end of the right screen flower long looper on the right side, the horizontal part of the right screen flower long looper driving rod is rotatably connected with the left side of the screen flower hook driving fan-shaped sheet through a right screen flower long looper driving connecting rod, the rotating shaft of the right screen flower short looper driving rod vertically penetrates, the horizontal part of the right screen flower short hook driving rod is rotationally connected with the right side of the screen flower hook driving fan-shaped piece through a right side left and right screen flower bidirectional hook driving connecting rod, the left screen flower frame is sleeved and fixed on the left screen flower frame fixing cylinder, one end of a swing arm of the left screen flower frame is fixed with a double-groove long hook positioned on the left side, the upper end of a rotating shaft of the right screen flower short hook driving rod is fixed with a left screen flower driving arm which moves together with the right screen flower short hook driving rod, one end of the left screen flower driving arm is fixed with a left screen flower hook extending to the left side, and a long-strip arc-shaped guide hole is supported between the double-groove long hook and the left screen flower;

the end part of the right net flower long hook is provided with a downward inclined hook, the end part of the left net flower bidirectional hook and the right net flower bidirectional hook penetrates through a horizontal right net flower threading hole, the ends of the left and right net flower bidirectional hooks are provided with vertical left net flower pushing wire grooves, the front and back sides of the end part of the double-groove long curved needle are respectively provided with a right net flower pressing wire groove and a left net flower pressing wire groove, the end part of the left net flower hook is arranged flatly, the sewing machine is provided with a left vertical screen flower threading hole, a right screen flower long hook, a left screen flower bidirectional hook, a right screen flower long hook, a left screen flower long hook, a right screen flower long hook, a left screen flower hook and a right screen flower hook which are sequentially and gradually heightened from bottom to top, a screen flower hook driving fan-shaped sheet is driven by a left screen flower driving groove and a right screen flower driving groove to swing and fixedly spliced with a sewing machine driving lining, so that the sewing machine driving lining drives the screen flower hook driving fan-shaped sheet to swing back and forth along the axis of a presser foot push rod, and the screen flower hook driving fan-shaped sheet drives the right screen flower long hook, the left screen flower bidirectional hook, the right screen flower bidirectional hook, the double-groove long hook and the left screen flower hook to.

Furthermore, the guiding hole is formed in the threading support, the other end of the threading support is provided with a vertical long-strip-shaped height adjusting hole, the threading support is fixed to one end of the threading fixing frame through an inner hexagonal bolt penetrating through the height adjusting hole and screwed tightly, and the other end of the threading fixing frame is sleeved and fixed to the upper end of the right net flower long looper fixing sleeve.

Furthermore, a cutting angle protection sheet capable of swinging back and forth is arranged on the front side of the single cutting presser foot through a screw and a pressure spring.

Furthermore, a lower cutting blade is clamped in the front opening of the single-cutting presser foot through a lower blade clamping plate, and the cutting edge of the lower cutting blade is positioned in the front opening of the single-cutting presser foot.

Furthermore, a vertical presser foot connecting sheet is fixed on the side wall of the single-cutting presser foot above the needle through hole.

Further, the height of the right mesh embossing groove is lower than that of the left mesh embossing groove.

The utility model discloses can only sew a stitch seam with six line seam machines on four needles of current crank arm formula, improve to three six line double-colored concatenations, can sew two parallel stitch seams simultaneously, two stitch seams (also called net flower) can be different colours, carry out the crossing net flower to hitting the look product, more can embody the individuality of product and the aesthetic feeling of seam lines, field such as sportswear, swimsuit very much. The utility model discloses the improvement of going on current crank arm formula four needles six lines sewing machine makes the utility model discloses a presser foot device and original presser foot device accessory can be exchanged, change at any time according to customer's needs, make things convenient for personnel's operation, more saved the transformation cost of equipment.

Drawings

Fig. 1 is a schematic front side three-dimensional structure of the present invention;

fig. 2 is a schematic diagram of a rear side three-dimensional structure of the present invention;

fig. 3 is a schematic diagram of the explosion structure of the present invention;

FIG. 4 is a schematic perspective view of the right net flower long hook of the present invention;

FIG. 5 is a schematic view of the three-dimensional structure of the left and right net-flower bidirectional hooks of the present invention;

FIG. 6 is a schematic view of the three-dimensional structure of the double-grooved long looper of the present invention;

fig. 7 is a schematic view of the structure of the motion state of the present invention;

fig. 8 is a schematic view of the structure of the threading mode of three needles and threads of the present invention.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The present embodiment is described in detail below with reference to the accompanying drawings:

the embodiment provides a double-thread stitching needle presser foot device for a crank arm type sewing machine, and please refer to fig. 1-8 in the attached drawings of the specification together.

As shown in figures 1-8, the double-thread stitching needle thread presser foot device for the crank arm type sewing machine comprises a single-cutting presser foot 1 and a screen flower hook driving fan-shaped sheet 2, the single-cutting presser foot 1 and the screen flower hook driving fan-shaped sheet 2 are penetrated through by a presser foot push rod of a sewing machine head, a right screen flower long looper fixing sleeve 3 and a right screen flower short looper fixing sleeve 4 are respectively arranged at two sides of a presser foot push rod penetrating hole of the single-cutting presser foot 1, a left screen flower shelf fixing sleeve 5 is arranged at the upper end edge of the presser foot push rod penetrating hole of the screen flower hook driving fan-shaped sheet 2, a rotating shaft of a right screen flower long looper driving rod 6 vertically penetrates through the right screen flower long looper fixing sleeve 3, a hook body is fixed at the lower end of the right screen flower long looper 7 on the right side, the horizontal part of the right screen flower long looper driving rod 6 is rotatably connected with the left side of the screen flower hook driving fan-shaped sheet 2 through a right screen flower long looper driving connecting rod 8, a rotating, a left and a right net flower bidirectional hooks 10 positioned on the right side are fixed at the lower end, the horizontal part of a right net flower short hook driving rod 9 is rotationally connected with the right side of a net flower hook driving fan-shaped piece 2 through a right side left and right net flower bidirectional hook driving connecting rod 11, a left net flower frame 12 is sleeved and fixed on a left net flower frame fixing cylinder 5, a double-groove long hook 13 positioned on the left side is fixed at one end of a swing arm of the left net flower frame 12, a left net flower driving arm 14 which moves together with the right net flower short hook driving rod 9 is fixed at the upper end of a rotating shaft of the right net flower short hook driving rod 9, a left net flower hook 15 extending to the left side is fixed at one end of the left net flower driving arm 14, and a long arc-shaped guide hole 16 is supported between the double-groove long hook 13;

the end part of the right long mesh hook 7 is provided with a downward inclined hook 17, the end parts of the left and right two-way mesh hooks 10 penetrate through a horizontal right mesh threading hole 18, the ends of the left and right two-way mesh hooks 10 are provided with a vertical left mesh pushing line groove 19, the front and back sides of the end part of the double-groove long looper 13 are respectively provided with a right mesh pressing line groove 20 and a left mesh pressing line groove 21, the height of the right mesh pressing line groove 20 is lower than that of the left mesh pressing line groove 21, the end part of the left mesh hook 15 is flatly arranged and provided with a vertical left mesh threading hole 22, the right long mesh hook 7, the left and right two-way mesh hooks 10, the double-groove long looper 13 and the left mesh hook 15 are sequentially and gradually heightened from bottom to top, the mesh hook driving fan-shaped sheet 2 is fixedly inserted with the sewing machine driving bush driving swing through the left and right mesh driving groove 23, so that the sewing machine driving bush driving fan-shaped sheet 2 swings back and forth along the axis of the presser foot pushing rod, the screen flower hook driving fan-shaped sheet 2 drives the right screen flower long hook 7, the left screen flower bidirectional hook 10, the right screen flower bidirectional hook 10, the double-groove long looper 13 and the left screen flower hook 15 to move back and forth along an arc-shaped track at the front side of the long strip-shaped needle hole 24 of the single-cutting presser foot 1.

In order to adjust the height of the guide hole 16, the guide hole 16 is arranged on the threading support 25, the other end of the threading support 25 is provided with a vertical long strip-shaped height adjusting hole 26, the threading support 25 is fixed at one end of the threading fixing frame 27 through a hexagon socket head cap screw which penetrates through the height adjusting hole 26 and is screwed, and the other end of the threading fixing frame 27 is sleeved and fixed at the upper end of the right net flower long looper fixing sleeve 3.

In order to prevent the finger from being injured by the needle moving up and down, a cutting angle protection sheet 28 capable of swinging back and forth is arranged on the front side of the single cutting presser foot 1 through a screw and a compression spring.

The lower cutting blade 30 is clamped in the front opening of the single cutting presser foot 1 through the lower blade clamping plate 29, and the cutting edge of the lower cutting blade 30 is positioned in the front opening of the single cutting presser foot 1.

The 1 lateral wall of the single-cutting presser foot of rectangular shape needle hole 24 top is fixed with vertical presser foot connection piece 31, and presser foot connection piece 31 mainly plays limiting displacement, also has this structure on primary equipment, the utility model discloses only improve the height at left side presser foot connection piece 31 fixed position, simultaneously with the 1 department excision of single-cutting presser foot at fixed position, form a bottom and be semicircular breach, like the left position of rectangular shape needle hole 24 in figure 3, in addition, the 24 right sides in the rectangular shape needle hole of single-cutting presser foot 1 still set up supplementary needle and perforate.

The utility model discloses the theory of operation: the utility model is installed on a star sharp brand crank arm type four-needle six-thread sewing machine (model FW-740TB) for replacing the original single-cutter presser foot group (i.e. presser foot device), in addition, the length of the needle fixing body of the needle chuck is shortened to about 1.4cm, the used needle model is UY128 or DPX17 series, and is changed into three needles, as shown in figure 8, during installation, the left and right screen flower driving grooves 23 of the screen flower hook driving fan-shaped sheet 2 are inserted with the sewing machine driving bush, when the sewing machine operates, the driving bush driving screen flower hook driving fan-shaped sheet 2 swings back and forth along the axis of the presser foot push rod, thereby driving the right screen flower long hook 7, the left and right screen flower bidirectional hooks 10, the double-groove long curved needle 13 and the left screen flower hook 15 to move back and forth along the arc-shaped track at the front side of the long-strip-shaped needle hole 24 of the single-cutter presser foot 1, for example, when the screen flower hook driving fan-shaped sheet 2 moves backwards, i, the rear side of the meshed hook driving fan-shaped piece 2 drives the right meshed long hook driving connecting rod 8 to move leftwards relatively, the right meshed long hook driving connecting rod 8 drives the right meshed long hook driving rod 6 to rotate anticlockwise, the right meshed long hook 7 is fixed at the lower end of the right meshed long hook driving rod 6, the hook part is bent and extends to the right side of the strip-shaped needle hole 24, so that the right meshed long hook 7 rotates anticlockwise, the inclined hook 17 at the end part of the right meshed long hook 7 moves outwards equivalently, the double-groove long hook 13 is fixedly connected with the meshed hook driving fan-shaped piece 2 through the left meshed flower frame 12 indirectly, so that the double-groove long hook 13 rotates anticlockwise equivalently, the right meshed press line groove 20 and the left meshed press line groove 21 at the end part of the double-groove long hook 13 move inwards, the meshed hook driving fan-shaped piece 2 rotates anticlockwise, the front side drives the right meshed short hook 9 to rotate clockwise through the left and right meshed bidirectional hook driving connecting rod 11, therefore, a left and a right net flower bidirectional hooks 10 fixed at the bottom of the left and the right net flower bidirectional hooks 10 rotate clockwise, a right net flower threading hole 18 and a left net flower thread pushing groove 19 at the end part of the left and the right net flower bidirectional hooks 10 move inwards relatively, at the moment, the left net flower thread pushing groove 19 also has the function of pushing a left bottom thread, a left net flower driving arm 14 fixed at the upper end of a right net flower short hook driving rod 9 also rotates clockwise to drive a left net flower hook 15 to rotate clockwise, the end part of the left net flower hook 15 is positioned at the left side of a strip-shaped needle thread hole 24 and continues to rotate clockwise, a left net flower threading hole 22 at the end part of the left net flower hook 15 equivalently moves outwards, the motion processes are detailed in figure 7, arrows in figure 7 are the motion directions of all moving parts, and similarly, when the net flower hook drives the fan-shaped piece 2 to move forwards, namely rotates clockwise, the whole operation process is opposite, so that the right net flower long, The end parts of the left and right net flower bidirectional hooks 10, the double-groove long loopers 13 and the left net flower hook 15 move back and forth along an arc-shaped track on the front side of the long-strip-shaped needle hole 24 of the single-cutting presser foot 1 to realize the staggered penetration of the bottom thread and the needle thread, and two parallel stitches are sewn at the same time.

Three needle lines respectively penetrate through three needles of a sewing machine head, as shown in fig. 8, the type of the needle is UY128 or DPX17 series, the needle can only penetrate through cloth up and down under the driving action of the sewing machine head, three vertical parallel contour lines of stitches are formed, a left bottom line sequentially passes through a left screen printing threading hole 22, a guide hole 16 and a left screen printing thread pressing groove 21 on the rear side of the double-groove long curved needle 13 from top to bottom, and is pushed to the left through a left screen printing thread pushing groove 19. The bottom thread on the right side firstly passes through the right screen printing threading hole 18 from outside to inside, then passes through the inclined hook 17 and finally passes through the right screen printing thread groove 20, the left bottom thread (also called left screen printing thread) passes through the left screen printing threading hole 22, the guide hole 16, the left screen printing thread groove 21 and the left screen printing thread pushing groove 19 to swing left and right to realize the mutual interlude with the needle thread on the leftmost side and the middle side to finish the screen printing of the left stitch, meanwhile, the bottom thread on the right side freely swings and pulls the right side and the middle needle thread to mutually interlude through the right screen printing threading hole 18, the inclined hook 17 and the right screen printing thread groove 20, and the parallel screen printing on the right side is realized.

The utility model can be used in series such as Japanese Dahe FD-62G sewing machine, Japanese flying horse FS-601 sewing machine, Taiwan famous worker MJ62G sewing machine, and can be used for improving and replacing the presser foot device of other brands.

Of course, the above embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. The utility model provides a crank arm formula sewing machine is with double-line concatenation needle line presser foot device which characterized in that: comprises a single-cutting presser foot (1) and a screen flower hook driving fan-shaped sheet (2), wherein the single-cutting presser foot (1) and the screen flower hook driving fan-shaped sheet (2) are penetrated through by a presser foot push rod of a sewing machine head, a right screen flower long looper fixing sleeve (3) and a right screen flower short looper fixing sleeve (4) are respectively arranged at two sides of a presser foot push rod perforation of the single-cutting presser foot (1), a left screen flower frame fixing sleeve (5) is arranged at the upper end edge of the presser foot push rod perforation of the screen flower hook driving fan-shaped sheet (2), a rotating shaft of a right screen flower long looper driving rod (6) vertically penetrates through the right screen flower long looper fixing sleeve (3), a hook body is fixed at the lower end of the right screen flower long looper fixing rod (7) at the right side, the horizontal part of the right screen flower long looper driving rod (6) is rotatably connected with the left side of the screen flower hook driving fan-shaped sheet (2) through a right screen flower long looper driving connecting rod (8), and a rotating shaft of a right screen flower, a left and a right net flower bidirectional hooks (10) positioned on the right side are fixed at the lower end of the left net flower bidirectional hook driving rod, the horizontal part of a right net flower short hook driving rod (9) is rotatably connected with the right side of the net flower hook driving fan-shaped piece (2) through a right side left and right net flower bidirectional hook driving connecting rod (11), a left net flower frame (12) is sleeved and fixed on a left net flower frame fixing cylinder (5), a double-groove long hook (13) positioned on the left side is fixed at one end of a swing arm of the left net flower frame (12), a left net flower driving arm (14) moving together with the right net flower short hook driving rod (9) is fixed at the upper end of a rotating shaft of the right net flower short hook driving rod (9), a left net flower hook (15) extending to the left side is fixed at one end of the left net flower driving arm (14), and a long arc-shaped guide hole (16) is supported between the double-;

the end part of the right long mesh hook (7) is provided with a downward inclined hook (17), the end parts of the left and right two-way mesh hooks (10) penetrate through a horizontal right mesh threading hole (18), the ends of the left and right two-way mesh hooks (10) are provided with a vertical left mesh pushing slot (19), the front and back sides of the end part of the double-slot long looper (13) are respectively provided with a right mesh pressing slot (20) and a left mesh pressing slot (21), the end part of the left mesh hook (15) is flatly arranged and provided with a vertical left mesh threading hole (22), the right long mesh hook (7), the left and right two-way mesh hooks (10), the double-slot long looper (13) and the left mesh hook (15) are sequentially and gradually heightened from bottom to top, the mesh hook driving fan-shaped sheet (2) is in driving, swinging and inserting connection with the sewing machine driving bush driving fan-shaped sheet (2) through the left and right mesh driving slots (23), so that the sewing machine driving mesh hook driving fan-shaped sheet (2) swings back and forth along the axis of the sewing machine driving push rod, the screen flower hook driving fan-shaped sheet (2) drives the right screen flower long hook (7), the left screen flower bidirectional hook (10), the right screen flower bidirectional hook, the double-groove long curved needle (13) and the left screen flower hook (15) to move back and forth along an arc-shaped track at the front side of the strip-shaped needle hole (24) of the single-cutting presser foot (1).

2. The double-thread stitch presser foot device for crank arm type sewing machine according to claim 1, characterized in that: the guide hole (16) is formed in the threading support (25), the other end of the threading support (25) is provided with a vertical long-strip-shaped height adjusting hole (26), the threading support (25) is fixed to one end of a threading fixing frame (27) through a hexagon socket head cap screw penetrating through the height adjusting hole (26) and screwed, and the other end of the threading fixing frame (27) is sleeved and fixed to the upper end of the right net flower long looper fixing sleeve (3).

3. The double-thread stitch presser foot device for crank arm type sewing machine according to claim 1, characterized in that: the front side of the single cutting presser foot (1) is provided with a cutting angle protection sheet (28) which can swing back and forth through a screw and a pressure spring.

4. The double-thread stitch presser foot device for crank arm type sewing machine according to claim 1, characterized in that: a lower cutting blade (30) is clamped in the front opening of the single cutting presser foot (1) through a lower blade clamping plate (29), and the cutting edge of the lower cutting blade (30) is positioned in the front opening of the single cutting presser foot (1).

5. The double-thread stitch presser foot device for crank arm type sewing machine according to claim 1, characterized in that: a vertical presser foot connecting sheet (31) is fixed on the side wall of the single-cutting presser foot (1) above the strip-shaped needle hole (24).

6. The double-thread stitch presser foot device for crank arm type sewing machine according to claim 1, characterized in that: the height of the right mesh flower line pressing groove (20) is lower than that of the left mesh flower line pressing groove (21).